linux-kernel - Re: [PATCH] kbuild: move -pipe to global KBUILD

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Message-Id: <1582381271.1karmgahx0.none@localhost>
Date:   Sat, 22 Feb 2020 09:24:14 -0500
From:   "Alex Xu (Hello71)" <alex_y_xu@...oo.ca>
To:     Nathan Chancellor <natechancellor@...il.com>
Cc:     Russell King <linux@...linux.org.uk>, linux-kbuild@...r.kernel.org,
        linux-kernel@...r.kernel.org, masahiroy@...nel.org,
        michal.lkml@...kovi.net
Subject: Re: [PATCH] kbuild: move -pipe to global KBUILD_CFLAGS

Excerpts from Nathan Chancellor's message of February 22, 2020 3:01 am:
> I used hyperfine [1] to run a quick benchmark with a freshly built
> GCC 9.2.0 for x86 and aarch64 and here are the results:
> 
> In both cases it seems like performance regresses (by 1% but still) but
> maybe it is my machine, even though this benchmark was done on a
> different machine than the one from my commit back in 2018.
> 
> I am not sure I would write off these results, since I did the benchmark
> 25 times on each one back to back, eliminating most of the variance that
> you described.
> 
> [1]: https://github.com/sharkdp/hyperfine
> 
> Cheers,
> Nathan
> 

What kernel version are you running? Do you have the 5.6 pipe reworks?